This invention relates to substituted phthalonitriles and substituted phthalocyanines, and to their use as lubricity-enhancing additives in lubricating fluids.
It is generally known that phthalocyanines are useful to enhance the lubricity of lubricating fluids. In addition, phthalonitriles may also be used as additives to enhance the lubricity of lubricating fluids. For example, ortho-phthalonitrile, when suspended or dissolved in a base fluid and subjected to high friction, reacts with metal surfaces at high temperatures to form, in situ, lubricating films of metal phthalocyanines. However, most phthalocyanines do not have melting points, and sublime or vaporize only under extremely reduced pressure and at temperatures exceeding 500.degree. C. These properties essentially preclude the use of phthalocyanines except as insoluble additives in liquid lubricants, or as solid lubricants. Their use as insoluble additives may be undesirable in many applications, because they may not remain suspended in the lubricating fluid during use.
Phthalocyanines and ortho-phthalonitriles which have been substituted with 4-aryloxy substituents are described in Snow, A. W. et al., 17 Macromolecules 1614 (1984) and U.S. Pat. Nos. 2,122,137 and 4,061,654. Phenoxy- and thiophenoxy-substituted phthalocyanines soluble in some organic solvents are described in Derkacheva, V. M et al., 50 Zh. Obshch. Khim. 2313 (1980). Fluorine-containing alkoxyphthalonitriles are disclosed in JP Patent App. No. 62-147840. However, these phthalocyanines are not suitable for use as an additive in lubricating fluids which offer high thermal stability.